But even then it's still only sustainable with a certain set of narrow assumptions, some of which are starting to become challenged. The U.S. only has a somewha

But even then it's still only sustainable with a certain set of narrow assumptions, some of which are starting to become challenged. The U.S. only has a somewhat sustainable system for the short term because of immigration and GDP growth. I still don't understand why defined contribution is vilified by the left when it's the only actually sustainable solution, resilient to political, economic, and demographic changes.